Myocardial ischemia results from insufficient blood flow to the heart muscle. Ischemia may occur chronically such as due to coronary artery disease or acutely due to sudden increased demand, embolism or vasospasm. Ischemia can lead to angina and eventually to myocardial infarction—permanent damage to the heart muscle. Moreover, both ischemia and infarction can trigger fatal arrhythmias.
Many patients who are equipped with implantable medical devices (IMDs) such as cardiac pacing devices experience ischemia. In these patients the ischemia can affect the efficacy of any stimulation therapy supplied by the IMD to the cardiac tissue.